Railway braking apparatus



June 1, 1943. c, s. SNAVELY RAILWAY BRAKING APPARATUS 5 Sheets-Sheet 2Filed Dec. 24, 1941 lll'll N m @QEQ m NAN Mar

June 1, 1943. c s. SNAVELY RAILWAY BRAKING APPARATUS 5 Sheets-Sheet 3Filed Dec. 24, 1941 5% .Ew .5 EN N MIMQ i wwrwwfwm MM? wk w a 1H ER MNQ.M. N

I I I l I lllllllllllllllll!llllllllllllllllllllllllllIlllll-IIIIIIIILJune 1, 1943- c. s. SNAVELY 2,320,802

RAILWAY BRAKING APPARATUS Filed Dec. 24, 1941 5 Sheets-Sheet 4 @KBRSQK BS $35 am y x W 5 SQN MM. k ww U W? n I Na m km MN L v ENN A n m R 1 R wkN l J L QN QW & mww E k Wm u @QQ MN) m n u u u u n a g g a a Q g a N n Hn J m n u g m u a u m Q mk fi mw mkin 4% 5 m Patented June 1, 1943EAILWAY BRAKING APPARATUS Clarence S. Snavely, Churchill Borough, Pa,as-

signor to The Union Switch & Signal Company, Swissvale, Ia., acorporation of Pennsylvania Application December 24, 1941, Serial No.424,338

34 Claims.

My invention relates to railway braking apparatus, and particularly tocar retarders of the type comprising wheel engaging braking bars locatedbeside a track rail and movable toward and away from the rail intobraking and nonbraking positions. More particularly, my inventionrelates to apparatus of the type described wherein the braking bars arearranged to be moved to their braking positions by means of one or morefluid pressure motors, and to be restored to their non-braking positionsby suitable biasing means.

One object of my invention is the provision of improved means forautomatically controlling the braking action of a car retarder inaccordance with the speed of a car passing therethrough.

Another object of my invention is the provision of improved timing meansfor measuring the speed of a car passing through a car retarder.

Another object of my invention is the provision of improved means forprogressively decreasing the braking force exerted by a car retarder asthe speed of a car being retarded by the retarder approaches a selectedone of a plurality of predetermined control speeds, and for releasingthe retarder when the selected control speed is reached.

A further object of my invention is the provision of means whereby thebraking action of r a car retarder may be controlled automatically inaccordance with the speed of a car passing through the retarder, ormanually at the will of an operator.

A still further object of my invention is the provision of means forproviding improved flexibility of operation of a fluid pressure operatedcar retarder by enabling the pressure which is supplied to the retarderto operate it to be graduated into manually selected levels.

According to my invention the stretch of track with which the retarderis associated is provided with a series of single rail track circuitseach of which includes an insulated rail section which is sufficientlyshort so that two wheels of a car cannot occupy the section at any onetime. Each track circuit includes a track relay, and a back contact ofall of the track relays in advance, whereby only one track relay will beenergized. at a time. sets into operation time measuring meanscomprising a source of constant frequency alter nating current, andmeans for counting the cycles of this source.

The means for counting the cycles of the When any track relay isenergized, it

source includes a pair of half-step relays which respond to alternatehalf cycles of the current, whereby each relay operates once during eachcycle of the alternating current, and a unit chain of counting relayswhich pick up successively one each time a selected one of the half-steprelays operates. The counting relays are arranged to continue to operateas long as the track relay which initiated their operation remainsenergized. Assuming that the frequency of the constant frequency sourceis 60 cycles, and that the unit chain includes 6 relays, it will be seenthat successive relays of the unit chain will pick up at intervals of 16milliseconds, and the chain will complete a full cycle of operationevery 100 milliseconds.

The time measuring means also includes a multiple chain of countingrelays so arranged that the relays of this latter chain will advanceprogressively one each time the unit chain completes a round trip ofoperation.

The time measuring means further includes means for restoring thecounting chain to starting position to initiate a new timing period eachtime a new track relay picks up.

The relays of the unit and multiple chains control other relays foreffecting a graduated reduction in the pressure of the fluid applied tothe operating cylinder of a fluid pressure operated car retarder inaccordance with the setting of a manually operable lever to cause theretarder to release when the speed of a car has been reduced to aselected speed.

The apparatus also includes means whereby the retarder can be controlledmanually independently of the manually operable lever.

Other objects and characteristic features of my invention will becomeapparent as the description proceeds.

I shall describe two forms of railway braking apparatus embodying myinvention, and shall then point out the novel features thereof inclaims.

In the accompanying drawings, Figs. 1a and lb are views which, whenplaced one above the other with Fig. 1a on top in such manner that thedotted lines leading to the bottom of Fig. 1a align with the dottedlines leading to the top of Fig. 1b, together constitute a view partlysectioned and partly diagrammatic illustrating one form of apparatusembodying my invention. Figs. 2a and 2b are views similar to Figs. 1aand 1b illustrating another form of apparatus embodying my invention.Fig. 3 is a table showing the method of connecting the front contacts ofcertain ones of the relays forming part of the apparatus illustrated inFigs. 1a, 1b, 2a and 2b to obtain predetermined control speeds.

Similar reference characters refer to similar parts in all three views.

Referring first to Figs. 1a and 1b, the reference characters I and ladesignate the track rails of a stretch of railway track over which carsnormally move in the direction indicated by the arrow under suchconditions that it is desirable to at times control the speed of thecars automatically. For example, the stretch of track here shown mightbe in a classification yard of the hump type through which cars moveunder the influence of gravity. It is obvious that in service of thiskind the speed of individual cars or strings of cars will vary throughwide limits depending among other things on the speed at which they goover the hump, the temperature,

the Weight of the car and its contents, and the condition of the car asto whether it is a free running car or otherwise.

In order to control the speed of the cars, the stretch of trackillustrated in the drawings is provided with a car retarder CR which inthe form here shown comprises two braking bars 2 and 3 extendingparallel with, and located on opposite sides of rail I, and two similarbraking bars 2a and 3a extending parallel with and located on oppositesides'of rail Ia.

The braking bars 2, 3, 2a and 3a are operated by a fluid pressure motorM (Fig. lb) comprising a cylinder 4 containing a reciprocable piston 5attached to one end of a piston rod 6. The braking bars 2, 3, 2a and 3aare operatively connected with the piston rod 6 through a suitablelinkwork here shown as comprising a bell crank I and a lever 8 pivotallysupported at point 9. When piston 5 occupies its extreme left-handposition, in which it is illustrated in the drawings, the braking barsoccupy their non-braking or ineffective positions in which they are outof engagement with the wheels of a car traversing the rails I and Ia.When piston 5 is moved to its right-hand position, however, as whenfluid pressure is admitted to the left-hand end of cylinder 4, thebraking bars 2, 3, 2a and 3a are moved toward the associated rails totheir effective or braking positions in which they will engage thewheels of a car traversing the rails I and Id, to retard the speed ofthe car.

The braking bars 2, 3, 2a and 3a are constantly biased to theirnon-braking positions by any suitable means, here shown as a spring IIIwhich is interposed in the cylinder 4 between the righthand end of thecylinder and the piston 5.

The motor M is controlled by two magnet valves VI and V2, eachcomprising a valve stem I2 biased to an upper position by means of aspring I I, and provided with an armature I3 and a winding, I4. Whenvalve VI is energized, as shown in the drawings, valve stem I2 of thisvalve is moved downwardly against the bias of spring I I, and a pipe I8which communicates with the left-hand end of motor M is then connectedwith atmosphere through a port I5. When valve VI is deenergized,however, pipe I8 is disconnected from atmosphere. and is connected witha pipe I6 leading to valve V2. When valve V2 is energized, valve stem I2of this valve moves downwardly, and connects pipe I6 with pipe I I whichis constantly supplied with fluid pressure, usually air, from a suitablesource not shown in the drawings, but when valve V2 is deenergized, asshown in the drawings, pipe I6 is then disconnected from pipe I1. Itwill be apparent, therefore, that when valve VI is energized,

the region of the cylinder 4 of motor M between the piston 5 and theleft-hand end of the cylinder is connected with atmosphere, so that thebraking bars of the car retarder will then be held in their ineffectiveor non-braking positions by the spring I0. When, however, valve VI isdeenergized and valve V2 is energized, fluid pressure wil1 be suppliedto the left-hand end of cylinder 4 of motor M, thus causing the brakingbars to move to their effective or braking positions. It will be obviousthat when the braking bars are moved to their braking positions, theywill exert a braking force which is proportional to the pressure of thefluid which is then supplied to the left-hand end of motor M.

The valves V are controlled in part by a plurality of pressureresponsive devices PHI-30 and P45-55, each comprising a Bourdon tube 2Iconnected to pipe I8 and hence subjected to the pressure of the fluid inthe left-hand end of motor M. Each Eourdo-n tube controls two contacts2222a and 22--22b. The pressure responsive devices P253il and PA E-55are so constructed and so adjusted that they will operate successivelyas the pressure in the region of cylinder I between the piston 5 and theleft-hand end of the cylinder increases. For example, for all pressuresbelow 20 pounds per square inch, the contact 22-2 2a of each of thesedevices is closed. If the pressure exceeds 20 pounds per square inch,however, the contact 22-221; of device P20-3IJ opens, and if thepressureexceeds 30 pounds per square inch, contact 2222b of devicePHI-30 closes. In similar manner, the pressure responsive device P 3555is adjusted to open its contact 22-22a at 45 pounds per square inch, andto close its contact 222b at 55 pounds per square inch. Of course, thesespecific pressures are not essential but are only mentioned for purposesof explanation.

The valves V are also controlled in part by a plurality of relays IPO,2P0, IPZiI-M, 2P2lI--30, IP45-55 and 2Pl555 which relays, in turn, arecontrolled by speed responsive apparatus in a manner which will bedescribed in detail hereinafter.

The valves V are further controlled by means of a manually operablelever L which, a here shown, is capable of assuming five positions,indicated by dotted lines in the drawings, and designated by thereference characters P0 to 124, inelusive. Operatively connected. withthe lever L are a plurality of contacts 25, 26, 21, 28 and 29. Contacts25, 26, 21 and 28 are closed, respectively, in the 100, pl, 122 and p3positions of lever L, while contact 29 is closed in the pl position, thep4 position, or any position intermediate these two positions.

The lever L will usually be located at a point remote from the brakingapparatus, as in the control cabin of a classification yard car retardersystem, and will be connected with the braking apparatus by means ofline wires extending from the control cabin to the braking apparatus.

The previously mentioned speed responsive apparatus for controllingrelays IPIJ, 2P5, I P2ii-3Il, 2P253!J, IP4555 and 2P45-55 comprises aseries of relatively short insulated control sections IT, 2T, 3T, 4T, 5Tand ET, which control sections are formed in the rail I. These controlsections will usually be of uniform lengths, .and their lengths may bevaried as conditions require, but the lengths of these sections willpreferably be such that two wheels of a car cannot occupy the samesection at any one time. A preferred length for these sections is 3 ft.1 /2 in.

Associated with each control section is a track relay designated by thereference character B with a prefix corresponding to the referencecharacter for the associated section. These track relays are sensitivequick acting relays, and each relay is connected in a track circuitwhich, when all of the track relays are initially deenergized and a pairof wheels moves onto any one of the track sections T, includes asuitable source of current here shown as a battery 30, a back contact 34of a relay ZSU, a back contact 33! of a relay ISU, a back contact 3! ofeach of the track relays in advance of the occupied section, the windingof the track relay of the oc cupied section T, the wheels and axle ofthe pair of wheels on the occupied section T, and the rail Ia.

When a track relay picks up due to the energy supplied over any one ofthe track circuits just described, if the track relay is aneven-numbered relay, relay 2SU will pick up by virtue of a circuit whichI shall describe presently and will open its back contact 34, and if thetrack relay is an oddnumbered relay, relay lSU will pick up by virtue ofa circuit which I shall also describe presently and will open its backcontact 33L However, when either back contact 34 of relay ZSU or backcontact 33| of relay ISU opens, the front contact 32 of the picked-uptrack relay will then be closed and Will have completed a branch circuitin multiple with the contacts 33l and 34 in series, which branch circuitwill maintain energy on the picked-up track relay as long as the pair ofwheels which caused the track relay to pick up remain on the associatedsection. For example, if track relay ITR picks up due to a pair ofcarwheels entering section IT, relay ISU will pick up and will open itsfront contact 33I, but track relay ITR will be maintained in itsenergized condition after front contact 33| opens until the pair ofwheels leaves section IT, by virtue of a branch circuit including frontcontact 32 of track relay ITR.

When any one of the track relays is energized, and a pair of wheels Wenters any section in rear of the section for the energized relay, thetrack circuit for such rear section will be held open at the backcontact 3! of the picked-up track relay, and the track relay for suchrear section will remain deenergized.

When a track relay is energized, and the pair of wheels which caused itto become energized enters the section next in advance, the frontcontact 32 of the energized track relay will remain closed long enoughto complete a track circuit for the advance relay which track circuitwill be similar to the circuit described above except that thi circuitwill include the front contact 32 of the picked-up relay in place of theback contact 34 of relay 2SU and the back contact 33! of relay ISU inseries. The reason why a track relay remains energized until the relaynext in advance picks up when the pair of wheels which caused the relayto become energized passes from the associated section to the sectionnext in advance is that the wheels will alway engage the advance sectionfor a brief interval of time before they will break contact with therear section.

It will be seen, therefore, that when no car is traversing the trackcircuited territory through the retarder, the track relays T will all bedeene1- gized. When, however, a car traverses the track circuitedterritory, as the forward pair of wheels enters each track section, thetrack relay for such section will pick up, and the track relay for thesection next in rear will release. As soon as the forward pair of wheelspasses out of section 6T, relay 6TB will release and will cause relayISU or ZSU to release. As soon as these relays are both released, thetrack circuit for each relay whose associated section is then occupiedby a pair of wheels will become completed at the back contacts 331 and34 of these relays. However, only the track relay for the section whichis then occupied by the leading pair of wheels in the track circuitedterritory will complete its pick-up stroke since the opening of the backcontact of this relay will interrupt the track circuits for all of therelays in the rear.

The speed responsive apparatus also comprises means for measuring thetime during which any of the track relays is energized to therebyprovide a measurement of the speed of the car.

In the particular form illustrated, this time measuring means comprisesa suitable source of constant frequency alternating current, illustratedin the drawing as an alternator A, and means for counting the cycles ofthis source. In actual practice, the source of alternating current willgenerally comprise the usual commercial power source.

The means for counting the cycles of alternating current includes twohalf-step relays PX and NX of the quick acting two winding polarmagnetic stick type and two oppositely poled half wave rectifiers 334and 35. The one winding 31a of relay PX is connected with alternator Aover a front contact 36 of a relay W, the rectifier 334 and a normalcontact 38 of relay NX, while the other winding 31b of relay PX isconnected with the alternator A over front contact 36 of relay W,rectifier 334, and reverse cont-act 39 of relay NX. In a similar manner,the winding 31!: of relay NX is connected with alternator A over frontcontact 36 of relay W, rectifier 35, and a normal contact 40 of relayPX, while the other winding 31b of relay NX is connected with alternatorA over front contact 36 of relay W, rectifier 35 and reverse contact 4|of relay PX. The rectifier 334 is poled to pass current during positivehalf cycles only, while the rectifier 35 is poled to permit current toflow during negative half cycles only.

With the relays PX and NX connected with al" ternator A in the mannerjust described, it will be apparent that when front contact 36 of relayW is open, both relays PX and NX will be deenergized. When, however,front contact 36 of relay W becomes closed, during the first half cycleof current which flows from alternator A winding 31a of relay PX orwinding 37a of relay NX Will become energized depending upon whether thehalf cycle is a positive or a negative half cycle. Assuming for purposesof illustration that the first half cycle is positive, the resultantenergization of winding 3M of relay PX will cause this relay to open itsnormal contact 40 and close its reverse contact 4!. The closing of comtact 4| will complete the circuit for winding 31b of relay NX, and as aresult, the first negative half cycle will cause winding 31b of relay NXto become energized, whereupon this relay will open its normal contact38 and will close its reverse contact 33. The closing of reverse contact39 will complete the circuit for winding 31b of relay PX, and during thenext positive half cycle winding 31b of relay PX will become energizedand will cause reverse contact ;4|' of relay PX to open, and normalcontact 40 to close. Contact at now being closed, the next negative halfcycle will energize winding 31a, of relay NX, with the result thatreverse contact 39 will open and normal contact 38 will close. describedcycle of operation will then start to repeat itself, and the relays PXand NX will continue to alternately close their normal and reversecontacts as long as the contact 39 re mains closed.

The relay W is controlled by the track relays R in such manner that thisrelay willbe energized whenever any one of these track relays isenergized, by virtue of, circuits which I shall describe shortly.

The relay NX is provided, in addition to the previously mentioned normaland reverse contacts 38 and 39, with a normal contact l24?.a and areverse contact 42-4227. Assuming for purposes of illustration that thealternator A has a frequency of 60 cycles, it will be apparent that whenthe relay NX is operating, these contacts will become alternately closedat intervals of of a second or 16 milliseconds. This rate will vary onlyto the extent that the frequency of the alternator A varies, whichvariation will be extremely small, particularly if the alternator Acomprises a commercial source of power.

The cycle counting means also comprises a unit chain of counting relaysIII to 6U arranged to pick up successively in response to the alternateoperation of the contacts 42- i2a and 4242b of relay NX, and a multiplechain of counting relays GM to 5M arranged to advance progressively oneeach time the unit chain completes a round trip'of operation. The relaysof both chains are of the quick acting neutral type.

Associated with the unit and multiple counting chains is a relay MX ofthe two winding polar magnetic stick type which serves to make theselection of the circuits for the relays of the multiple group necessaryto cause them to pick up in succession in response to each round trip ofoperation of the unit chain, and a similar relay UX, the function ofwhich will be made clear presently.

The operation of the timing means as a whole is as follows: When thetrack relays T are all deenergized, as is the case when no car istraversing the stretch of track shown in the drawing, the relays of bothtiming chains, and the associated relays W, ISU, ZSU, NX, PX, MK and UKare all deenergized. When a car starts to traverse the stretch of trackshown in the drawing, relay ITR will pick up first for reasons whichwill be apparent from the foregoing description, and the picking up ofthis relay will complete a circuit for relays W, ISU, ill and thewinding 4-8 of relay UK in series, which circuit may be traced from theterminal B of a suitable source of direct current not shown in thedrawings, through the winding of relay W, a back contact 3333b of eachof the track relays ETR, ETR, 4TB, 3TB, and 2TB, front contact 3333a oftrack relay I'I'R, the winding of relay ISU, a back contact 44 of eachof the relays 2U to 6U, inclusive, of the unit counting chain, a backcontact 45 of each of the relays BM to 5M of the multiple countingchain, winding 48 of relay UX, wires 4t and 41, and the winding of relaylU to the other terminal C of the source. Relays W, ISU and [U willtherefore pick up immediately,

The above aeeasoa and relay UA will reverse its armature to open. itsnormal contacts and close its reverse contacts.

The picking up of relays Ill and ISU completes a stick or holdingcircuit for these relays passing from terminal B through the winding ofrelay W, a back contact. 33-431) of each of the track relays 6TB, 5TB,4TB, 3TR and 2TB, front contact 3333a of track relay ITR, the winding ofrelay ISU, front contact 49 of relay ISU,

wires 5% and ti back contact 52 of relay 2U, front contact 53 of relayIU, and the winding of relay ill to terminal C. The function of thesestick circuits will be made clear presently.

The picking up of relay W completes at its front contact 35 thepreviously described operating circuits for the relays PK and NX andthese relays therefore start to alternately operate on alternate halfcycles of the alternator A in the manner described hereinbefore.

Since relays W and IU are both picked up when the relays NX and PX startto operate, the first time reve se contact 4242b of relay NX becomesclosed, it completes a pick-up circuit for relay 2U passing fromterminal 13 through front contact 43 of relay W, reverse contact 42-421)of relay NX, wire 55, front contact 54 of relay IU, and the winding ofrelay EU to terminal C. Relay 2U therefore picks up and interrupts atits back contacts 444 and 52, respectively, the previously describedpick-up and stick circuits for relay l U, and completes at its frontcontact 53 a stick or holding circuit which is similar to the previouslytraced stick circuit for relays ISU and !U with the exception that thislatter circuit includes a back contact 52 of relay 3U, front contact 53of relay 2U and the winding of relay 2113 in place of a back contact 52of'relay 2U, front contact 53 of relay H17, and the winding of relay lU.Relay 9U, therefore, now becomes deenergised, while relay 2U remainsenergized as long as relay 3U remains deenergized.

.W'hen normal contact 42l2a of relay N X again closes, it completes apick-up circuit for relay 3U which is similar to the correspondingpickup circuit just traced for relay EU, and which ill therefore beapparent from an inspection of the drawing. Relay 3U therefore picks upand interrupts both the pick-up and stick circuits for relay 2U whichcauses relay EU to release. The picking up of relay 3U also completes apickup or holding circuit for this relay similar to the previouslytraced pick-up or holding circuit for relays NJ and 2U.

When relay NX next closes its reverse contact, relay 4U will pick up andrelay 3U will release, and when relay NX next closes its normal contact,relay EU'will pick up and relay .U will release and so on, until acomplete cycle of operation of the unit chain is completed. When thishappens, if section IT is then still occupied, relay IU will again pickup by virtue of circuit connections between the tU and IU relays similarto those between any two succeeding relays of the chain, and will startthe operation of the chain over again. It will be seen, therefore, thatthe relays ill to EU will continue to climb around and around as long astrack relay I TR, remains energized. It will also be apparent that ifthe frequency of the alternator A is 6i) cycles, so that the contacts42-4211 and 62-421; become alternately closed at intervals of 16milliseconds, the time spacing between the picking up of successiverelays-U will be 16 milliseconds, and the chain will complete a roundtrip of operation in exactly 100 milliseconds.

The front contact 49 of relay ISU, in addition to being included in thepreviously described stick circuits for the relays IU to (ill, is alsoin cluded in a pick-up circuit for the starting relay OM of the multiplechain, which latter circuit may be traced from battery B through thewinding of relay W, back contact 33-331) of each of the track relaysGTR, 'I'R, 4TH, 3TB. and 2TB, front contact 3333a of track relay ITR,the winding of relay ISU, front contact 49 of relay lSU, wire 59, a backcontact 60 of each of the relays 5M, 4M, 3M, 2M and IM of the multiplechain, and the winding of relay OM to terminal C, It will be seen,therefore, that as soon as relay ISU becomes energized following theenergization of track relay ITR, relay OM of the multiple chain willpick up.

With relay OM picked up, when relay 3U picks up during the first roundtrip of operation of the unit chain, it will complete at its frontcontact 64 a circuit for the one winding 65 of the transfer relay MK,and this relay will thereupon open its normal contact 66-66a and willclose its reverse contact 66--6Bb. This circuit includes in addition tofront contact 64 of relay 3U, front contact 63 of relay OM, as will beobvious from an inspection of the drawings. The circuit will bei comeopened as soon as relay 3U releases, but since relay MX is of themagnetic stick type, contact 66-6622 will remain closed until this relayis again energized in the direction to close its normal contact.

As a result, when relay GU of the unit chain picks up during the firstround trip of operation, a pick-up circuit is completed for relay IMpassing from terminal B through front contact 43 of relay W, frontcontact 61 of relay 6U, reverse contact 66-66b of relay MX, frontcontact 62 of relay OM, and the winding of relay IM to terminal C. RelayIM thereupon picks up, and completes a stick circuit passing fromterminal B through the winding of relay W, back contact 33-33b of eachof the track relays BTR, 5TB, 4TH, 3TB and 2TB, front contact 33--33a oftrack relay ITR, the winding of relay ISU, front contact 49 of relayISU, wire 50, a, back contact 60 of each of the relays 5M, 4M, 3M and2M, a front contact El of relay IM and the winding of relay IM toterminal C. This stick circuit serves to retain relay IM energized afterrelay 8U releases as will be obvious.

The picking up of relay [M in addition to con1- pleting its own stickcircuit also interrupts at its back contact 63 the pick-up circuit forrelay OM, and this latter relay therefore releases.

When relay 30 picks up during the second round trip of operation of theunit chain, the resultant closing of contact 64 completes a circuit forthe other winding 68 of relay MX including front contact 63 of relay IM,and relay MX then opens its reverse contact lit-66b and closes itsnormal contact 6666a.

With normal contact 6666a of relay MX closed, when relay 6U of the unitchain picks up during the second round trip of operation of this chain,the resultant closing of its front contact 61 completes a pick-upcircuit for relay 2M including front contact 62 of relay IM. This lattercircuit will be apparent from an inspection of the drawing withoutfurther detailed description. Relay 2M thereupon picks up and interruptsthe previously traced stick circuit for relay 1M and completes a stickcircuit for itself similar to the previously traced stick circuit forrelay IM.

Onthe third round trip of the unit chain since front contact 63 of relay2M is now closed, the resulting closing of front contact 64 of relay 3Uwill complete another circuit for winding 65 of relay MX which willcause this relay to again open its normal contact lit-66a and close itsreverse contact 666Eb, and when relay 6U picks up, the closing of itsfront contact 61 will complete a pick-up circuit for relay 3M. Relay 3Mwill thereupon pick up and relay 2M will release. In a similar manner iftrack section IT remains occupied long enough on the fourth and fifthround trips of the unit chain, relays 4M and 5M will pick up and relays3M and 4M will release.

It will be seen, therefore, that each time the unit chain progresses toand including the EU relay, the multiple chain will advance its actionby one relay, Accordingly, assuming that the frequency of the alternatorA is 60 cycles so that the unit chain completes a round trip ofoperation each milliseconds, the picking up of each progressive relay ofthe multiple chain represents a period of 100 milliseconds. In theparticular embodiment of my invention shown provision is made forcounting up to 500 milliseconds by the picking up of the M relays, afterwhich, of course, another 100 milliseconds may be counted by permittinganother round trip of the unit chain, making a total of 600 millisecondswith the circuits as shown.

It will also be seen that the relay MX merely serves to make thenecessary circuit selection of the M group of relays so that eachpick-up action of the EU relay of the unit chain will advance themultiple group of relays by one relay.

The function of the hereinbefore referred to stick circuit for relay IU,and of the stick circuits for each of the other U relays of the unitchain is to maintain these relays energized during the interval of timewhich elapses between the opening, at contact 42-42a or 42-421) of relayNX, of the pick-up circuit for the relay whose stick circuit is thenclosed and the picking up of the relay next in advance in the chain.

The stick circuits for the relays of the multiple chain similarly serveto maintain the M relay which last became energized in its energizedcondition during the interval which elapses between the opening of itspick-up circuit at contact 6666a or 66'o6b of relay MK, and the pickingup of the relay next in advance. In other words, the stick circuits forboth chains function to keep the chains in operation as long as thetrack relay which started the operation remains energized.

When the car which caused track relay ITR to pick up advances to thepoint where relay 2TR picks up, the resultant opening of back contact33-33b of track relay ZTR interrupts any of the stick circuits whichthen happens to be closed for any of the relays of either the unit andmultiple chains, and relays W and lSU therefore immediately becomedeenergized. As soon as re lay W becomes deenergized, it opens thepick-up circuits for each of the relays of both chains, and since thepick-up and stick circuits for the relays of both chains are then allopen, these relays all become deenergized. The deenergization of relay Walso momentarily stops the operation of the PX and NX relays.

As soon as the back contacts of all of the U relays and the backcontacts of all of the M relays all become closed, thereby checking thatthese relays are all deenergized, a pick-up circuit for relay EU iscompleted at front contact 3333a of track relay 2TB and current flowsfrom battery B through the winding of relay W, a back contact 33-431) ofeach of the track relays 6TH, TB, 4TB and 3TB, front contact 3333a oftrack relay 2TB, the winding of relay ESU, back contact 10 of each ofthe relays 2U to EU, inclusive, a back contact H of each of the relaysOM to 5M, inclusive, the winding T2 of relay UX, wire 46, and thewinding of relay ill to terminal 0. Since relays ISU and W are bothincluded in this circuit, these relays and relay I U all pick up.Furthermore, since the winding 12 of relay UX is included in thiscircuit, this relay reverses its armature, thereby opening its normalcontacts and closing its reverse contacts.

When relay ZSU picks up, it completes a stick circut for relay IU, and apick-up circuit for relay OM which circuits are similar to the circuitswhich were completed by relay ISU following the picking up of trackrelay ITR with the exception that these latter circuits each include afront contact 33-3311 of track relay ZTR, the w nding of relay ZSU, andfront contact 13 of relay ZSU in place of front contact 33-331 of trackrelay ITR, the winding of relay ISU, and front contact 49 of relay ISU.

When relay W picks up, it sets the counting chains into operation, andthese chains then function to measure the time required for the pair ofwheels of the car to traverse section 2TB in the same manner as thesechains functioned to measure the time for the forward pair of wheels ofthe car to traverse section IT. The circuits for the various relays ofthe two counting chains Will all be similar to those previouslydescribed except for the fact that each stick circuit will now includefront contact 33-33a of track relay 2TB. the winding of relay 2SU andfront contact 13 of relay 2SU in place of front contact SIB-33a of trackrelay ITR, the winding of relay ISU and rent contact 49 of relay ISU.

When track relays 3TB and 5TB subsequently pick up, the relay ISU willbe picked up and the apparatus will function in the same manner as whenrelay ITR was picked up. Similarly, when the relays 4TB and 6TB pick upthe apparatus will function in the same manner as when relay ZTR ispicked up. It Will be seen, therefore, that as a car advances throughthe track circuited territory, the relays ISU and ZSTJ alternate intheir action depending upon whether an odd or an even-numbered trackrelay is then picked up. Each SU relay checks that all relays of bothcounting chains have become deenergized before it can pick up afterwhich the IU relay of the unit chain picks up for the beginning of a newtiming period.

The back contacts 33! and 34 of the ISU and ZSU relays are included inthe pick-up circuits for the track relays for check purposes. As long asthe track relays become successively energized, the multiple frontcontacts of the track relays by-pass the back contacts of the SU relaysand accordingly freely permit the relay next in advance to pick up.After the leading car axle leaves section 6T, it will be apparent thatthe relay 6TB. will have to release before any of the other track relaysin the rear can pick up. Accordingly, all other multiple front contactsof the track relays are then opened, and it is then necessary that bothSU relays be released in order that their back contacts 33!, and 34 mayclose and permit another track relay in rear of track relay 6TB to pickup. This check is provided in order to prevent the counting relays fromdoubling back to another section without first having been reset to thestarting point.

The function of the W relay is to provide the necessary separatecontacts for supplying operating energy to the NX and PK relays and tothe counting chain during the energized periods of the track circuits.

It should be pointed out that while I prefer to provide a source ofalternating current controlling the energization of the half-step relaysPK and NX to effect the energization of the successive relays of thetiming chains, the alternating current source and associated half-steprelays may be replaced by any suitable motor means which willalternately close the contacts 42-420, and 42- 322) at a known fixedrate.

It will be obvious that the particular relays 0f the unit and multiplechains which are picked up at any one time are a measure of the timethat any section which is then functioning as a measuring section hasbeen occupied. It will also be obvious that since the sections have aknown fixed length, the speed of a car passing through the car retardercan be determined from the time during which a section is occupied by apair of wheels. It follows, therefore, that the relays of the countingchains which are picked up when a pair of wheels vacates a section whichis then functioning as a measuring section serve as a measure of theaverage car speed while the car is traversing a length equal to thelengths of the measuring sections. For example, assuming that the tracksections T are all 3 ft. 1 in. long, and that the alternator A has afrequency of cycles per second, if a track section remains occupied for266 milliseconds, which is the time it will remain occupied with anaverage car speed of 8 miles per hour, when the section becomes vacated,relays 2M and 6U will be picked up, and it follows that if these relaysare picked up when a measuring section becomes vacated, it is anindication that the car which caused themto pick up was traveling at anaverage speed of 8 miles per hour. Similarly, if a track section whichis serving as a measuring section is occupied for 600 milliseconds,which corresponds to a car speed of 3.1 miles per hour, relays EU and 5Mwill be picked up to indicate that the car speed is 3.1 miles per hour.The car speeds corresponding to various relay combinations are shown intabular form in Fig. 3, and by reference to this table the car speed forany particular relay combination can be determined.

The previously referred to relays lP lfi-55, iP2ii3-il and IPOconstitute one group of relays, and the previously referred to relaysEP-iS-ES, 2P2i!3t and 2P0 constitute another group of relays, for socontrolling the valves Vi and V2 as to eifect an automatic steppedreduction in the pressure of the fluid supplied to the motor M as thespeed of a car passing through the car retarder approaches apredetermined control speed which depends upon the setting of lever L,and for effecting the full release of the retarder when this particularcontrol speed is reached. These two groups of relays are caused tofunction alternately, according as an odd or an even-numbered tracksection is acting as a speed measuring section, by means of the UK relaywhich it will be remembered closes its normal contacts 5l'i55a,5'l-5'ia, 5;58a and 5859a or it reverse contacts Kit-53b, 5l5'|b, Et-'58?) and 5959b according as an odd-numbered track relay lTR, 3TB or5TB, or an even-numbered track relay 2TB, 4TB or 6TH. i picked up, andeach P relay is provided with a plurality of control circuits controlledby different contact combinations of the relays of the unit and multiplecounting chains.

In the particular form of my invention illustrated in the drawings, eachP relay is provided with a diiierent control circuit for each of the pl,112 and p3 positions of the lever L, making three control circuits foreach relay. The control circuits for the IP and 2P relays are similarexcept for the fact that each control circuit for each of the lP relaysincludes a normal contact of the UK relay, whereas each control circuitfor each of the 2P relays includes a corresponding reverse contact ofthe UX relay. These control circuits may be varied as conditionsrequire, but as shown in the drawing they are so arranged that whenlever L occupies its pl position, which position I shall term forconvenience its high speed position, relay |P45-55 or 2P45-5'5 will pickup when relays IM and U are simultaneously picked up, the relay |P30 or2P2530 will pick up when the relays 2M and 2U are simultaneously pickedup, and the relay IPO or 2P0 will pick up when the relays 3M and IU aresimultaneously picked up. When, however, lever L occupies its p2position, which I shall term its medium speed position, relay IP55 or2P45- will pick up when relays 2M and IU are simuL s taneously pickedup, relay IP2D30 or 2P2839 will pick up when relay 3M is picked up andrelay IPO or 2P9 will pick up when rela AM is picked up. Similarly, whenlever L occupies its 133 position, which I shall term its low speedposition, relay lP-l55i5 or 21 45-55 will pick up when relays 2M and Allare both picked up, relay IP20- 38 or 2P2il3ii will pick up when relays3M and 4U are simultaneously picked up, and relay IPO or 2P0 will pickup when relays 5M and 2U are simultaneously picked up.

By virtue of circuits which will be described in detail hereinafter,When lever L is first moved to its pl, p2 or p3 position, the fluidpressure motor M will be supplied with fluid at full line pressure,which I shall assume for purposes of explanation to be 100 pounds persquare inch. If the relay lP45-5 :3 or 2P i5-5-5 subsequently picks up,the pressure in motor M will be automaticall reduced to a pressure ofbetween 45 and 55 pounds per square inch, if relay lP20-3fl 0r 2P20-30picks up, the pressure in motor M will be automatically reduced to apressure or between 20 and 30 pounds per square inch, and if the relayIPO or 2390 picks up, motor M will be vented to atmosphere to effect theautomatic release of the.

car retarder.

The p!) position of lever L is its off position and is the position towhich the lever is moved when it is desired to manually release theretarder.

The p4 position of lever L is provided to obtain the full braking forceavailable irrespective of the speed of a car which is being retarded,and when the lever occupies this position, the speed control apparatusis ineffective to control the retarder as will appear presently.

Associated with the relays lP45-55, IP20-30 and IF?) is a stick relayISP which is picked up whenever any one of these pressure control relaysis picked up, and associated with the pressure control relays 2P455'5,2P2030 and 2P0 is a stick relay 281? which is picked up whenever any oneof these last mentioned speed control relays is picked up.

Since a time element is involved from the time a pair of car wheelsenters a track circuit which is then functioning as a measuring sectionuntil a speed determination can be made, it is necessary that anypressure control that is obtained by the picking up of any one of the Prelays in response to an immediately preceding speed determination bemaintained for a suiiicient length of time to overlap the intervalrequired to make the new speed measurement. Thus, once a given pressurecontrol has been obtained by means of one of the P relays, it should bemaintained as long as successive speed measurements indicate the needfor that particular pressure. It is for the purpose of obtaining thisoverlap action that the two groups of pressure control relays areprovided, and this overlap is obtained by the use of energy stored in acondenser which is shunted around each pressure control relay P inseries with one or more resistances, and which renders the relay slowreleasing. A condenser is used because it guarantees a definite timeelement in a shorter space of time than is possible with schemesutilizing the saturation of the relay to obtain the time element.

The stick relays SP and ZSP are provided to prevent the pressure controlrelays from starting their timing period at the time of their pickupinstead of waiting until the track section the occupancy of which causedthem to pick up is vacated. Thus the SP relays on each successive speedmeasurement will maintain energy on any pressure control relay which isthen energized until such time as the next track circuit becomesoperated, in which event the reversing of the UK relay will release theSP relay which was previously energized and will thereby permit thecondenser associated with the energized pressure control relay tofunction to delay the release of the pressure control relay until a newspeed measurement is completed.

Due to the fact that conditions change from time to time in acarretarder yard due, for ex ample, to weather changes, seasonal differencein the lading of the cars, etc., it is desirable to be able to readilyvary the car speeds at which the P relays function, and to this end, Ipermanently connect each of the contacts of the timing relays of theunit and multiple chains which are provided for controlling the P relaysto a different pair of terminal posts mounted on a terminal board TB(Fig. 1b). This terminal board is also provided with a plurality ofterminal posts 8|, 82 and 83 which are permanently connected to a wireleading to contact 26 or lever L, with a plurality of terminal posts 84,85 and 86 which are permanently connected to a Wire 9| leading tocontact 21 of lever L, and with a pin rality of terminal posts 81, 88and 89 which are permanently connected to a wire 92 leading to contact29 of lever L. This terminal board is further provided with a pluralityof terminal posts 93, 94 and 95 which are permanently connected to awire I02 leading to the movable contact finger 51 of relay UK, with aplurality of terminal posts 96, 91 and 98 which are permanentlyconnected to a wire I03 leading to the movable finger 58 of relay UK,and with a p1urality of terminal posts 99, I00 and IUI which arepermanently connected to a wire I04 leading to the movable finger 59 ofrelay UX.

With the terminal board B arranged in this manner, when it is desired toeffect the operation of one of the P relays at any particular car speedfor a particular lever setting, reference is first made to the chartshown in Fig. 3 to determine which combination of contacts of the unitand multiple groups come closest to the desired speed, and the contactsof this combination are then connected in series by means of jumpers,between one of the terminal posts which is permanently connected to thelever contact which is closed for the particular lever setting, and oneof the terminal posts which is permanently connected to the wire Hi2,I03 or IE4 leading to the contact of the UK relay which is included inthe particular control circuit for the desired P relay. For example, ifit is desired to cause the IPE] and 2P5) relays to operate at a speed of4 miles per hour when lever L occupies its 113 or low speed position, itis necessary to connect a contact of the 5M relay and a contact of the2U relay in the circuit for these relays, and this is accomplished byconnecting a jumper IE5 from the terminal post 89 to the one terminalpost which is connected with front contact 1? of relay 2U, a jumper I05from the other terminal post which is permanently connected with frontcontact ll of relay 2U to the one terminal post which is permanentlyconnected with the contact 89 of relay 5M, and a jumper ID! from theother terminal post which is permanently connected with the terminalpost 80 of relay 2U to terminal post IIlI. In actual practice the relaycontact which is connected to each terminal post will be indicated bysuitable marking means associated with the terminal post and the otherterminal posts which are not connected with relay contacts will beproperly identified by suitable markings to indicate the proper circuitwith which they are associated.

As shown in the drawings, all parts occupy the positions which theynormally occupy when no car is passing through the retarder, that is tosay, all relays are deenergized, lever L occupies its p!) or offposition, and valve V2 is deenergized. Valve VI, however, is energizedover a circuit which may be traced from terminal B of the source throughcontact 25 of lever L, line wire H5, wires H6, H1 and H8, and thewinding of valve VI to terminal C. As was pointed out hereinbefore, whenvalve V2 is deenergized and valve VI is energized, cylinder 4 of motor Mis disconnected from the source of fluid pressure and is connected withatmosphere, and the braking bars are held in their inefiective ornon-braking positions by the spring Ill. The contact 22--22a of each ofthe pressure responsive devices 3? is closed, and the contact 22-422?)of each of these devices is open.

In explaining the operation of the apparatus as a whole, I shall assumethat a car which is to be retarded is approaching the retarder, and theoperator wishing to cause the car to leave the retarder at the highestspeed for which the apparatus is designed moves lever L from its pl] or01? position to its 'pI or high speed position. The movement of thelever L from its ml to its pI position will interrupt at its contact 25the circuit which was previously closed for valve VI, and will completeat its contact 29 a circuit for valve V2 which may be traced frombattery B through contact 29 of lever L, wire I09, back contact IIllIIlla of relay IPIJ, back contact IIII-IIIla of relay 2P6, back contactlit-JIM of relay iP30, back contact IIll-I Hla of relay -2P2B-3il, backcontact IlIl-Ilfi of relay IP45-55, back contact Ilfl-i Idea of relay2P45-55, wires I I I, H2 and I l3, and the winding of valve V2 toterminal C. Valve VI will therefore become deenergized and willdisconnect cylinder 4 of motor M from atmosphere, and valve V2 willbecome energized and will connect cylin-' der 4 with pipe II, therebyadmitting fluid to cylinder 4 at full line pressure. The braking barswill therefore immediately move from their ineffective or non-brakingpositions to their effective or braking positions.

When the first axle of the car enters track section IT, track relay ITRwill pick up and will cause the W, ISU and IU relays to immediately pickup. The picking up of track relay ITR will also cause the winding 48 ofrelay UK to become energized, but since the normal contacts of thisrelay are already closed, the energization of this relay will not causeany operation of the relay contacts. The picking up of the W relayimmediately starts the operation of the half-step relays PX and NX, andsince relay ISU is then energized, the counting chain starts to functionto measure the speed of the car. If the speed of the car is suflicientlyslow to cause the IM and 5U relays to pick up, a circuit will becomeclosed for pressure control relay IP45-55 and stick relay ISP passingfrom terminal B through contact 26 of lever L, wire 90, terminal post8|, jumper I 1%, front contact T5 of relay 5U, jumper I29, front contactE8 of relay IM, jumper I2I, terminal post 93, wire 22, normal contact5l5la of relay UX, wire I2I, resistor I22, the winding of relay IP4555,wire I46, and the winding of relay 5551? to terminal C. This circuitincludes a resistor I24 and a condenser I25 in series connected inmultiple with the resistor I22 and the winding of relay IP45-55 inseries. Relay IP4555 and stick relay ISP will therefore pickup and willcomplete a stick circuit pass ing from terminal B of the source throughfront contact I21 of relay ISU, wire I28, normal contact 56-5l3a ofrelay TJX, wire I23, back contact I39 of relay ISP, wire LEE, backcontact I32--I32a of relay IPll, wire I33, back contact !34I34a of relay[1 29-30, wire I35, front contact I36 of relay IPli5--55, the resistorI22, the winding of reiay !P45-55, wire I46, and the Winding of relayISP to terminal C. This stick circuit also includes the condenser I25and resistor I24 referred to hereinbefore. It should be noted that sincethis stick circuit includes front contact I21 of relay ISU, back contactI34l34a of relay iPZii-Sfi and back contact I32-i32a of relay lPfi, whenrelay IP4555 becomes energized under the conditions just described, itwill subsequently remain energized until relay IPZU-ZIB or relay lPlipicks up or section iT becomes vacated even though the relays 5U and IMof the counting chain which caused it to become energized subsequentlyrelease.

The picking up of relay IP45-55 interrupts at its back contact I IU-IIlia the circuit which was previously closed for valve V2 and completesat its front contact IIOI lllb a circuit for valve VI passing frombattery B through contact 29 of lever L, wire Iliil, back contactIIfl-IIIla of relay lPO, back contact IIIl-I Illa of relay 2P0, backcontact IIOI Illa of relay IP2U-3ll, back contact lit-I Illa of relay2P20-30, front contact Hlll lflb of relay IP45-55, wire I40,-contact22-222) of pressure responsive device P ES-55, wires II! and H8, and thewinding of valve V i to terminal C. Valve V2 therefore becomesdeenergized and disconnects motor M from the source of fluid pressure,and valve VI becomes energized and vents motor M to atmosphere. Valve VIwill continue to vent motor M to atmosphere until the pressure in thecylinder 4 decreases to 55 pounds per square inch, at which time contact22-221) of pressure responsive device P4555 will open and willdeenergize valve VI. If the pressure in the cylinder 4 decreases below45 pounds per square inch, the resultant closing of contact 22-221 ofpressure responsive device P4555 will complete another circuit for valveV2, and current will flow from battery B through contact 29 of lever L,line wire I09, back contact IIO-IIOa of relay IPO, back contact IIOIIOaof relay 2P0, back contact IIO--I Illa of relay IP20-30, back contactIIO-I Illa. of relay 2P20-30, front contact IIO--IIOb of relay IP4555,wire I40, contact 2222a of pressure responsive device P4555, wires H2and H3, and the winding of valve V2 to terminal C. Valve V2 willtherefore become energized and will connect motor M with the source offluid pressure until the pressure increases to 45 pounds per square inchat which time contact 22-421) of pressure responsive device P45-55 willopen and will deenergize valve V2. It will be seen, therefore, that whenrelay IP45-55 becomes energized, the fluid in the cylinder 4 of motor Mwill be reduced to a pressure of between 45 and 55 pounds per squareinch, and will be subsequently maintained at this pressure as long asrelay [PAS- remains energized.

If the speed of the car is sufficiently slow while the leading pair ofwheels is traversing section ITR to cause relays 2M and 2U of themultiple and. unit counting chains to both become picked up, a circuitwill then be completed for relay IP2030 passing from terminal 13 of thesource through contact 26 of lever L, wire 90, terminal post 82, jumperI4I, front contact 15 of relay 2U, jumper I42, front contact I9'of relay2M, jumper I43, terminal post 96, wire I03, normal contact BE -58d ofrelay UX, wire I44, resistor I41, the winding of relay IP2030, wiresI45, I56 and I 46, and the winding of relay ISP to terminal C. Thislatter circuit also includes a condenser I48 and a resistor I49 inseries connected in multiple with the resistor I 41 and the winding ofthe relay IMO-30 in series. Relay |P20-30 will therefore pick up, andrelay ISP will remain picked up. 'When relay IP20--30 picks up, itcompletes a stick circuit passing from. terminal B through front contactI21 of relay ISU, wire I28, normal contact 5656a of relay UX, wire I29,front contact I30 of relay ISP, wire I3I, back contact I32-I32a of relayIPO, wire I33, front contact !34-l34b of relay IP20--30, resistor I41,the winding of relay IP2030, wires I45, I56 and I45, and the winding ofrelay ISP to terminal C. This stick circuit includes the condenser I48and resistor I41 referred to hereinbefore. This stick circuit for relayIP2030 will maintain this latter relay energized until relay ISUreleases or relay IPD picks up.

The picking up of relay IP2II3!J interrupts at its back contact IIO-IIlia any circuit which was previously closed for either valve V2 orvalve VI, and completes at its front contact IIO-I I 0b another circuitfor valve VI passing from. terminal B through contact 29 of lever L,line wire I09, back contact lID-Hlla of relay IPO, back contact IIOlHiaof relay 2P0, front contact Nil-JIM) of relay IP2!!35. wire I49, contact22-222) of pressure responsive device P2030, wire H8, and the winding ofvalve VI to terminal C. Valve V2 if it is not already deenergized whenthis circuit becomes closed will become de energized, and valve VIwill'become energized to thereby again vent fluid from motor M. When thepressure of the fluid in cylinder 4 of motor M decreases to 30 poundsper square inch, contact 22--22b of pressure responsive device P2030will open and will deenergize valve VI, and if the pressure in thecylinder of motor M decreases to 20 pounds per square inch, contact2222a of pressure responsive device P20-30 will close and will completeanother circuit for valve V2 which is similar to the circuit just tracedfor valve .VI with the exception that this latter circuit includescontact 22-22a of pressure responsive device P20-30, wire II 3, and thewinding of valve V2 in place of contact 22-222) of pressure responsivedevice P20-30, wire H8 and the winding of valve VI. It will be seen,therefore, that when relay IP20-30 becomes energized under theconditions just described the pressure responsive device P2030 willfunction to reduce the pressure of the fluid in cylinder M to a pressureof between 20 and 30 pounds per square inch.

If the car which is traversing the stretch of track shown in the drawinghas been slowed down by the car retarder sufficiently to permit relays3M and IU to pick up while the leading pair of wheels is traversingsection ITR, relay IPO will become energized by virtue of a circuitpassing from terminal B of the source through contact 26 of lever L,wire 90, terminal post 83, jumper I50, front contact 11 of relay IU,jumper I5I, front contact 80 of relay 3M, jumper I52, terminal-post 99,wire I04, normal contact 59-59:]. of relay UX, resistor I53, the windingof relay IPO, Wires I56 and I46, and the winding of relay I SP toterminal 0. This latter circuit includes a condenser I54 and a resistorI55 in series connected in multiple with the resistor I53 and thewindingof relay IPO in series. Relay [P0 will therefore pick up andsince this pick-up circuit includes relay ISP, relay I SP will remainenergized. When relay IPO becomes energized, it completes a stickcircuit passing from terminal B through front contact I21 of relay I SU,wire I28, normal contact 56-56a of relay UX, wire I29, front contact I30of relay ISP, wire I3I, front contact I32I32b of relay IPIl, resistorI53, the winding of relay IPO, wires I56 and I46, and the winding ofvrelay ISP to terminal C. This stick circuit also includes the condenserI54 and the resistor I55 which are included in the pick-up circuit forrelay IPD. This stick circuit will maintain relay IPO energized untilthe leading pair of wheels vacates track section I'I'R.

The opening of back contact IIO--I I 0a of relay IPO interrupts allcircuits which were previously closed for ither valve VI orvalve V2,while the closing of front contact I I 0I I05 of this relay completes acircuit for the valve VI passing from terminal B through contact 29 oflever L, line wire, I09, front contact IIO-IIOb of relay IPO, wires II6, II! and H8, and the winding of relay VI to terminal C. Valve VItherefore becomes energized and vents the fluid in cylinder M toatmosphere to thereby effect the release of the retarder.

I shall now assume that with lever L in its pl position, the leadingpair of wheels of a car pass out of section I'I'R and into section 2TBwhile relay IP45-55 is energized. When this happens relay ISU willrelease and relay ZSU will pick up to initiate a new timing period inthe manner previously described. When relay ISU releases, it willinterrupt atits front contact I2I the stick circuit which waspreviously' closedg'for relay IP4555 and-relays I-Pfi5'-55 and ISP willtherefore both become deenergized. Due, --how ever, to the con-denser'I25 and-resistor I24 asthe exceptionthat" this latter circuit includesreverse;o ontact- 5I5'Ib of relay UX -and-the winding of relay 2P45-'-55together with the-associated condenser IBI and associated resistors IGIand IE2 inplace-"of the-contact 5'I5Ia-of relay UK and' the -w-inding-ofrelay IP45-55 together with :the-associated condenser I25 and resistorsI24 and I22. As soon afterrelay 2P45 55 pick up as relay iP4555releases; the -relay 21 45- 55 -will become effective 3 to control thevalvesVI and V2 in the same manner that these valves were previouslycontrolled by the relay IP45-155.

If when leverL occupies its pl position; the leading pair of wheelsof,a,car -which is being retarded ;.passes*from section-lTR- to 2TB.when either 'theprcssure control relay 'IP2II 3II or IPO is energized,the --pressure control relay 21 -130, orZPO will subsequently berendered effective to control'the valves VI and Y2 as soon as,a newmeasurement Ofspeed can, be madeif I i the, speed cfthe car;has.notchanged until-the new measurement is completed.

1 t will: beapparent,that a new speed ,measurement will be made eachtimethe leadinglpair of wheels-enters anew track section, andif the carpeedsuplbetween wo speed measurem n s, when the next speed measurementis ,made, the pressure control relays will automatically ,function toincrease the braking pressure. It isbelievedrthat this,operationxwill'lbe a parent from i an inspectioni of the ,drawingswithout the necessity for describing vit indetail.

'When lever L. is moved .to its 102 position, the pparatus funct ons nthe sam m nner a w e i i moved to, its I po it-ion with th cXc p ionthat under these conditions the pressure control relays-areprovided-with different control circuits to cause ,thepressure, of .thefluid supplied to ,motorM .tohereduceflin raduated t a the speed of acar approaches the control speed corresponding .to, this lever.nositionand there- .tarder to ,be automatically released when the sp ed"cfnth ar reache this con ro spccdf l control ,circuitfor the I'Pl4 5.5.5.,rclay,underthese nd t n i esircm t rminaui of thesourthnoughcontact 21 .ofleyer L, wire SI. terminal post .85, v jumper-I63,front;c,onta;t .'I5 of relay ,IU, jumper lfill frontncontact I8 ofrelay 2M. jumper I,,6,5,,,terminal post fikiwire I112, ,normal I22, thewinding of relayIP45,55, wire I46.

and the winding of relay ISP to terminal C. This. circuit includes thecondenser I and the resistor I24. 'The circuit'for the relay 2P4 555 is.thecame as that just-traced for the relay IF45 55 except for thedifference which will be apparentfrom an inspection of the drawings andfrom thejoregoingdescription.

The circuit for relay IBM- when leverL occupies its p3-position-passesfrom terminal -13 1 through front contact 2? of lever L, wire 9I ,ter-

minal post"85,'-jumper 'I65,Tfront cont-act 'lil of relay- 3M, jum perI57, terminal post" 9?,wire I03, normal contact5858a of relay 'UX, wireI44, resistor I41; the Winding of relay IP25-3il, wires I45,- I55andIMi, and 'the'winding'of relay ISP to terminal *0. This circuitincludes thecondenser I48 and resistor MS as will be obvious.

"The circuit for the relay iPO when lever L occupies its 112 positionpasses from terminal' B throughcontact 21 of lever L, wire 9|, terminalpost 55, jumper I53,fr0nt contactfifl of relay 4M,'jumper I59, wire I54,normal contact5$i- 59a of relay UX, resistor and the winding of-relayIPO in series in 'multiple with condenser I54-and resistor I55, WiresI55 and I45, and the winding of relay ISP to terminal C.

When -lever L occupies its'p3 position, theicircuit for relay IP55passes from terminaLB through contact 28 of lever-L, wire '92,'terminalpost--8'I,jumper- I13, front Contact 2'5 oftrelay 2U, jumper I'M, frontcontacttfi of relay 2M,

jumper I15, terminal-posted wire I02, normal,

contact 5l5la of relay UX,'wire IEI, resistor 4 22- and-the winding ofrelay IP i555 in'series in multiplewith condenser I25 and resisto I24,wire I46, and the'winding-of relay. ISPto terminalB.

"The circuit for relay IP29-30 when lever L occupies its 113 positionpasses from'terminal 2B of the source through contact .28 of .lever' L,Wire SZ, terminal post 88, jumper I70, front contact'I'I of relay 4U,jumper I'II, front contact "I9 of relay -3M, wire I12, terminal post 98,wire I93, normal contact '5358a of relay U'X, wire I44, resistor I41 inseries-with'the winding of relay IPZEEI3B inlmultiple with condenser I48and-resistor I49 invseries, wire I45, I and I46 and the winding of relayISP toterminal C.

"The circuit 'forrelay I'PO when lever L occupies-itspfi positionpasses'from battery B through contact 28 of lever L,-wire 92, terminalpost 89, jumper I05, front contact I! of rela '2U, jumper I05, frontcontact of relay 5M, jumper I01, terminal post IBI, wire I04,normal-contact59-59a of relay UX, resistance I53 and the winding ofrelay I PO connected in multiple with the condenser I54 and theresistorI55 in series,

"wire I56, and the-winding of relay ISP to terminalC.

The'circuits for each of the relays'2P45-55, =2P20-30 and 2P0 when leverL occupies its 102 and p3 positions differ from the circuits 'justtraced for therelays IP45-55, IP26-35 and IPO inthe same manner thatthe'circuitsfor the relays-2P4555,'2P2030- and 2P0 difier fromthecircuits for the relays IP45-55, IP2U---30 and I'PO when lever "Loccupies its pl position, and willbe apparent from'an inspection of thedrawing without further description.

'If the operator moves lever L to its p4 position, the speed responsiveapparatus is rendered ineffective to control the retarder and underthese conditions the valve V2 becomes energized and remains energized byvirtue of a circuit which passes from battery B through contact 29 oflever L, line wire I09, back contact IIfB-I IBa of relay IPQ,back-contact IIO-I Illa of relay 2P0, back contact IIOIIGa of relayIP2530, back contact IIII--I Illa of relay 2P20-3!i, back contactIIll--I IOa of relay IP4555, back contact HIE- IIUaof relay 2P45-55,wires III, H2 and H3, and thewi-nding of valve'Vz to terminal 0. Sincevalve :VZremains energized under these conditions the braking bars areheld in their braking positions by fluid at full line pressure, and theretarder is effective to exert its maximum braking force during theentire time the car is passing through the retarder.

It will be apparent from the foregoing that with railway brakingapparatus constructed in the manner shown in Fig. 1 the operator byproper operation of the lever L may cause the braking bars to becomeautomatically released when the speed of a car which is being retardedby the retarder decreases to any one of a plurality of selected speeds,which speeds may be varied as conditions require. It will also beapparent that when the speed of a car is being reduced by the retarder,the pressure of the fluid supplied to the fluid pressure motor of theretarder will be reduced in two stages prior to the actual release ofthe retarder, thereby providing a more effective control of the carretarder than would otherwise be possible. It should be particularlypointed out that the track circuit lengths as well as the alternatingcurrent frequency of the alternator A can be varied depending upon thecondition obtaining and the accuracy desired. Ordinarily 60 cyclealternating current would be used since this is the usual commercialfrequency available and one that can be accurately controlled in view ofits general use for operating electric clocks. If desired an entirelyindependent source or any desired source of frequency may be used.

It will also be apparent that the counting chain combinations and thenumber of steps involved in each chain is merely a matter of choicedepend-- ing upon the conditions to be served. If desired,

in cases where longer timing is needed it would r-zi be feasible tointroduce three groups of multipliers instead of restricting theapparatus to the two groups shown. For such an arrangement the secondgroup would of course rotate in a manner similar to the first group, andthe third group would then be used to total the number of revolutionsmade by the second group. This principle could be carried on as far asis necessary.

It should further be pointed out that the number of speeds that may beselected by the operator from the lever L is purely a matter of design.The attached drawings show a high, medium and low speed. This may beamplified to any desired number of speeds that may be needed.Furthermore. the number of pressure reductions is dependent only on theamount of the equipment which is provided. Moreover there is nonecessary or essential relationship between the number of speed controlsand the number of pressure reductions that may be provided.

Referring now to Fig. 2, the apparatus here illustrated is generallysimilar to that shown in Fig. 1. However, the apparatus shown in Fig. 2includes certain additions that have been made to permit it to performadditional functions, and embodies certain circuit changes which permita reduction in the number of relays required and the number of contactswhich are necessary on other relays, as will be made clear.

As shown in Fig. 2, an additional pressure responsive device Put-80 isprovided to provide an additional braking pressure. The device Floissimilar to the previously described devices PHI-30 and P55 except forthe fact that its contact 22-22a is adjusted to open at pounds persquare inch, and its contact AZ-22b is adjusted to close at pounds persquare inch.

Furthermore, as shown in Fig. 2, a standard control lever LI similar tothe lever L has been provided to permit the car retarder CR to bemanually controlled wholly independently of the speed responsiveapparatus, together with a manually operable switch MS which functionsto shift the control of the car retarder from one lever to the other.

As shown in the drawing, the switch MS occupies the position in whichthe lever L is effective to control the retarder, and in which itscontacts ZOO-400a and 20I2DIa are closed, and its contacts 200200b and20I20Ib are open. When it is desired to control the retarder by means ofthe lever LI, this switch is reversed to open its contacts 20E220Da. and20i20la and to close its contacts 2OEI-20Gb and 2!!I20Ib.

The control of the car retarder by means of lever L! is as follows. Whenthis lever occupies its p0 or off position in which it is shown in thedrawings, all contacts of the lever with the exception of the contact 25are open, and under these conditions valve V2 is deenergized and valve VI is energized over a circuit which passes from terminal B throughcontact EDI-40H) of switch MS, contact 25 of lever LI, wire 202, Wire203, and the winding of valve VI to terminal C. Since valve V2 isdeenergized, pipe I! is disconnected from pipe I5, and the supply offluid pressure to cylinder 4 of motor M is therefore cut oil, and sincevalve VI is energized, cylinder 4 is connected with atmosphere. Thebraking bars are therefore held in their ineffective or non-brakingpositions by the spring I0. The contact 22 22a of each of the pressureresponsive devices P is closed, and the contact 22-221) of each of thesedevices is open.

I shall now assume that the operator wishes to make a comparativelylight brake application. To do this he moves lever L! from its to its plposition, thereby opening contact 25 and closing contact 26. The openingof contact 25 interrups the circuit which was previously closed forvalve VI at this contact, and valve VI therefore now becomes deenergizedand disconnects pipe i8 from port I5. The closing of contact 26completes a circuit for valve V2, and current flows from battery 13through contact 20I-20Ib of switch MS, contact 25 of lever LI, line wire204, contact 22-22a of pressure responsive device PHI-30, wire 2G5, andthe winding I 4 of valve V2 to terminal C. Valve V2 therefore becomesenergized and connects pipe I! with pipe I 6, so that fluid at full linepressure is now supplied to cylinder 4, thus causing the braking bars tomove to their effective or braking positions. As soon as the fluid incylinder 4 reaches 20 pounds per square inch, contact 22-42%. ofpressure responsive device P263ll will open and will interrupt thecircuit just traced for valve V2. Valve V2 will then become deenergizedand will cut off the supply of flu d to cylinder 5 of motor M until thepressure in the motor again decreases below 20 pounds per square inch atwhich time valve V2 will again become energized and will again admitfluid to the cylinder. If the fluid in the cylinder 4 of motor Mincreases to a pressure of 30 pounds per square inch for any reason,contact 2 ='-22b of pressure responsive device P20-30 will become closedand will complete a circuit for valve VI which passes from terminal Bthrough contact 20i-20ib of switch MS, contact 23 of lever Li, line Wire2104, contact 22-22b of pressure responsive device P2 39, an asymmetricunit 206 in its low resistance direction, and the winding I5 of valve VIto terminal C. Valve VI will therefore become energized and will ventfluid from cylinder 4 until the pressure again decreases to 30 poundsper square inch and permits contact. 220--22 b to be open. It will beseen, therefore,

that when lever Ll occupies its pl position, the

braking bars will be held in their braking positions by a pressure ofbetween 20 and 30 pounds per square inch.

If the operator desires to make a more powerful brake application, hewill move lever Li to its p2 position in which contact 21 is closed.Under these conditions, valve VI will be deenergized and valve V2 willbecome energizedover a circuit which passes from battery B throughcontact 2M2Glb of switch MS, contact 2.! of lever Li, line wire 201,contact 22-2211 of pressure responsive device P45-55, wire 225, and thewinding M of valve V2 to terminal C. Fluid pressure will therefore nowbe admitted to cylinder 4 of motor M until the pressure of the fluid inthe cylinder increases to 45 pounds per square inch, at which timecontrol 22--22a of pressure re sponsive device P45-55 will open and willdeenergize valve V2. If the pressure in cylinder i now increases to 55pounds per square inch, contact 22-22b of pressure responsive device-Ps5--55 will become closed and will complete another circuit for valve Vithis latter circuit passing from battery B through contact Eel-20H) ofswitch MS, contact 2'! of lever Ll, line wire 20?, contact 22-22b ofpressure responsive device P45--35, asymmetric unit 206 in its lowresistance direction, and winding 14 of valve V! to terminal C. Valve Vlwill therefore become. energized and will exhaust fluid from cylinder 4until the pressure decreases to that at which contact 22-221) ofpressure responsive device 1 45-55 opens. It will be apparent,therefore, that when lever Ll occupies its p2 position, the braking barswill be held in their braking positions by a pressure of between 45 and55 pounds per square inch.

If the operator moves lever LI to its 113 position, valve V2 will thenbecome energized over a circuit which passes from battery B throughcontact 22-i2!3lb of switch MS, contact 28- of lever LI, line wire 298,contact 22-22a of pressure responsive device PIG-43G, wire 265, and thewinding M of valve V2 to terminal C. Under these conditions, fluid willbe supplied to cylinder 4 of motor M until the pressure in the cylinderreaches '70 pounds per square inch which is the pressure at whichcontact 22-22:; of pressure responsive device Pit-80 opens. If thepressure in cylinder 4 now increases to 80 pounds per square inch,

contact 22-221) of pressure responsive device- P'I i!8ii will becomeclosed and will complete still another circuit for valve VI. for valve VI may be traced from battery B through contact Mil-201D of switchcontact 28 of lever Ll, line wire 20B, contact 2222b of pressureresponsive device Pl8l, asymmetric unit 206' in its low resistancedirection, and the winding l4 of valve VI to terminal B. Valve V! willtherefore become energized until the pressure in cylinder of motor Magain decreases to 89;

pounds per square inch. It will be seen, therefore, that when lever L!is moved to its p3 position, cylinder 4 is supplied with fluid at apressure of between '70 and 80 pounds per square inch, so that thebraking bars exert a. corresponding braking force.

If the operator desires to cause the braking bars to exert their maximumbraking force, he will move lever Ll to its 104 position. Under theseconditions, valve V2 will become energized and will subsequently remainenergized by virtue of a circuit which passes from battery B throughThis latter circuitv contact fill-2M1 of switch MS, contact 29-01 leverLI, line wire209, wire 20.5, and the. windingv of valve V2 to terminalC. It will be apparent, therefore, that under these conditions thebraking bars will be held in their braking positions-by fluid at fullline pressure.

t should be observed that if the operator moves lever LI from a positioncorresponding to.

a higher braking force to a position corresponding to a lower brakingforce, the apparatus immediately and automatically reduces the brakingpressure to a value corresponding to the new position of the lever in amanner which will be.

apparent from the drawings without tracing the sequence of operation indetail.

When lever Ll occupies any one of itsp i p2, 12.3-

or p41 positions, so that the braking bars occupy their brakingpositions and the operator wishes to restore the braking bars to theirnon-braking result, the supply of fluid pressure to the cylinder 4 ofmotor M will be cut oil and the fluid which. was previously supplied tothe cylinder will be.

vented to atmosphere. The braking bars will therefore move under theinfluence of the spring H! to their ineffective or non-brakingpositions. When the braking bars reach their non-braking positions, allparts are restored to the positions in;

which they are shown in the drawings.

Associated with lever L is a relay LP which, provides a means fordecreasing the general level.

of the braking pressure at the will of the operator when the carretarder is being controlled by-the. speed responsive apparatus. Therelay LP is provided with a control circuit which passes from: terminalB through contact Zfll-Zflla of manu-- ally operable switch MS, contact29 oflever L, contact 2 of a manually operable switch MSI,

line wire 2m, and the winding of relay LP to terminal C. With relay LPcontrolled over this.

circuit it will be apparent that when the car retarder is beingcontrolled by lever L, if contact. 2H of switch MSI is then closed,relay LP willv be picked up in all positions of lever L except the piposition. It will also be apparent. thatrelay LP can be released at anytime by operating the switch MSI to open the contact 2| I.

In actual practice the switch MSI will usually be a push button of thestick type which is built into lever L, and which is arranged to beretained in either of its two positions by suitable detent means.

Only two pressure control relays IP and IPO.

are provided in Fig. 2. The relay IP has associated therewith a stickrelay ISP and is provided with three pick-up circuits one for each ofthe pl, 322 and p3 positions of lever L.

When lever L occupies its pl position, the pickup circuit for relay ISPpasses from battery B.

through contact 2fi02i30a of manually operable switch MS, contact 26 oflever L, wire 90, terminal post 8|, jumper H9, front contact of relay5U, jumper front contact 18 of relay lM, jumper 12!, terminal post 93, aresistor 2L9.

in series with the winding of relay IP connected in multiple with acondenser 22I in series with resistor 228, and the winding of relay l-SPto. It will be noted that this circuit.

terminal C.

includes front contact I of relay 5U and front contact I8 of relay IM inseries, and it will be apparent, therefore, that when lever L occupiesits pl position, relay IP will pick up if the speed of a car passingthrough the retarder becomes less than that at which the relays 5U andIM pick up, namely 11.6 miles per hour.

When lever L occupies its 02 position, the pickup circuit for relay IPthen passes from terminal B of the source through contact 200-200a ofmanually operable switch MS, contact 21 of lever L, wire 9!, terminalpost 84, jumper I63, front contact I5 of relay IU, jumper I64, frontcontact 18 of relay 2M, jumper I65, terminal post 94, resistor 2 I 9 inseries with the winding of relay IP connected in multiple with acondenser 22I in series with a resistor 220, and the winding of relayISP to terminal C. This circuit includes front contact of relay IU inseries with front contact I8 of relay 2M, and it follows that when leverL occupies its p2 position, relay ISP will pick up if the speed of a carpassing through the retarder becomes less than 9.8 miles per hour.

When lever L occupies its p3 position, the pick-up circuit for relay IPthen passes from terminal B through contact 200--200a of manuallyoperable switch MS, contact 28 of lever L, wire 92, terminal post 81,jumper I13, front contact I6 of relay 2U, jumper I14, front contact 80of relay 2M, jumper I15, terminal post 95, re-

- sistor 2? in series with the winding of relay IP I connected inmultiple with the condenser 22I in series with a resistor 220, and thewinding of relay ISP to terminal C. This circuit includes front contactI6 of relay 2U in series with front contact 80 of relay 2M, and it willbe seen that when lever L occupies its p3 position, relay IP will becomepicked up if the speed of the car passing through the retarder becomesless than 9.1 miles per hour.

Relay IP is also provided with a plurality of stick circuits each ofwhich includes terminal B of the source, a front contact 2I5 of adifferent one of the U relays, wire 2H5, back contact 2I'I- 2IIa ofrelay ISPO, wire 23I, front contact I of relay ISP, front contact 2I8 ofrelay IP, resistance 2I9 in series with the winding of relay IPconnected in multiple with condenser 22! in series with resistor 220,and the winding of relay ISP to terminal C. The front contact 2I5 of atleast one of the U relays is always closed when .the unit counting chainis operating and it will be seen, therefore, that when relay IP oncepicks up it will remain picked up either until the unit chain stopsoperating, or until relay ISPO picks The relay IPO likewise hasassociated therewith a stick relay ISPO and is provided with threepick-up circuits one for each of the pl, p2 and p3 positions of lever L.When lever L occupies its pl position, the pick-up circuit for relay IPOpasses from terminal B through contact 200200a of manually operableswitch MS, contact 26 of lever L, wire 90, terminal post 83,

jumper I59, front contact 11 of relay IU, wire I5I, front contact 80 ofrelay 3M, jumper I52,

terminal post 99, the resistor 222 in series with the winding of relayIPO connected in multiple with a condenser 224 in series with a resistor223, and the winding I SP0 to terminal C of the Since relays IU and 3Mpick up whensource.

, ever the speed of a car traversing the stretch of track shown in thedrawing is less than 6.7 miles per hour, it will be apparent that when 1lever L occupies its pl position, the relay IPO will pick up if thespeed of a car traversing the stretch of track shown in the drawingdecreases to a speed of less than 6.7 miles per hour.

When lever L occupies its p2 position, relay IPO will then becomeenergized if the speed of a car traversing the stretch of track in thedrawing decreases below a speed of 5.3 miles per hour by virtue of acircuit which passes from terminal B through contact 200200a of manuallyoperable switch MS, contact 21 of lever L, wire 9|, terminal post 86,jumper I68, front contact of relay 4M, jumper I69, terminal post I00,resistor 222 in series with the winding of relay IPO connected inmultiple with a condenser 224 in series with a resistor 223, and thewinding of relay ISPO to terminal C.

When lever L occupies its p3 position, relay IPO will then becomeenergized if the speed of a car traversing the stretch of track in thedrawing decreases below a speed of 4 miles per hour by virtue of acircuit which passes from terminal B through contact ZOO-400d ofmanually operable switch MS, contact 28 of lever L, wire 92, terminalpost 89, jumper I05, front contact ll of relay 2U, wire I06, frontcontact 80 of relay 5M, jumper I01, terminal post IOI, resistor 222 inseries with the winding of relay IPO connected in multiple with acondenser 224 in series with resistor 223, and the winding of relay ISP0 to terminal 0.

Relay IPO is further provided with a plurality of stick circuits each ofwhich passes from terminal B through front contact 2I5 of a differentone of the U relays, wire 2I6, front contact 2I'I2I'Ib of relay ISPO,front contact 2|8 of relay IPO, resistor 222 in series with the windingof relay IPO connected in multiple with condenser 224 in series withresistor 223, and the winding of relay ISPO to terminal C.

Referring now particularly to the speed responsive portion of theapparatus shown in Fig. 2, relay W has been eliminated, and theenergizing circuits for the half-step relays PX and NX previouslydescribed in connection with Fig. 1 have been modified to include afront contact 2I2 of relay ISU or a front contact 2I3 of relay 2SU inplace of front contact 36 of relay W. It will be apparent, therefore,that when either relay ISU or relay ZSU picks up, the half-step relaysPX and NX will immediately start to operate and will continue to operateas long as the relay which initiated the operation remains energized.

Relay UK has also been eliminated in Fig. and the initial pick-u circuitfor the IU relay which becomes closed when the operation of the unitcounting chain is initiated by the picking up of any one of theodd-numbered track relays ITR. 3TB or 5TB. has been modified to includea back contact I3'I3a of relay 2SU in place of the winding of the Wrelay, and a back contact 255 of relay ISPO and a back contact 226 ofrelay ISP in place of the winding 48 of the relay UX. Tracing thiscircuit in detail for the condition when track relay 5TB, is picked up,for example, this circuit passes from terminal B through back contact33-331) of track relay ETR, front contact 33--33a of track relay S'I'R,the winding of relay ISU, back contact 13-13:; of relay ZSU, a backcontact 44 of each of the relays 2U to EU, inclusive, a back contact 7and thewinding of relay IU to terminal C.

'I'heinitial pick-up circuit for the IU relay which becomes closed whenthe operation of the counting chain is initiated by the picking up ofany of the even-numbered track relays ZTR, 4TR-and-6TR in Fig. 2 hasbeen modified in a manner similar to the circuit controlled by theodd-numbered track relays, and will be apparent from the above and froman inspection of the drawing without further detailed description.

It should be pointed out that since the initial I pick-up circuits forrelay IU each include a back contact 225 of relay ISPO anda back contact226 of relay ISP, the relay ISU or 2SU will not pick up in Fig. 2 unlessrelays ISP and ISPO are both deenergized. This check insures that the SPrelays have released between counting operations and permits theelimination of the alternate series of pressure control relays shown inFig. 1.

It should also be pointed out that this change makes possible theelimination of the UK relay, and reduces the pick-up circuits for the IUrelay to a single series of back contacts instead of a double set asshown in Fig. l.

The OM relay has been eliminated in Fig. 2, and the stick circuits forthe remaining M relays and fcr'the U relayshave been modified to includein addition to the front contact 4-9-4911 of the ISU relay or a frontcontact 13-131] of the relay ESU depending upon whether the iSU or 2SUrelay is then energized, a back contact of the SU relay which isdeenergized. That is to say, when the relay ISU is energized, the stickcircuits for each of the M or U relays includes in addition to the frontcontact 49-492) of relay ISU, back contact 'l3-13a of relay 2SU, andwhen relay ZSU is energized, the stick circuits for each of the U or Mrelays includes in addition to the front contact 13-131) of relay ZSU,back contact 49-69:: of relay lSU. Except for the modification 'justnoted, and a modification of the stick a circuit for the relay 3U whichI shall describe presently, these stick circuits are otherwise identicalwith the circuits previously described in connection with Fig. 1.

The pick-up circuits for the U and 'M zrelays in Fig. 2, with theexception of the pick-up circuit for relay 3U and the pick-up circuitfor the 'IM relay, are identical with the corresponding circuits showninFig. 1 exceptffor the fact that front contact 43 of relay W has beenornittedfrom these circuits. This contact has been omitted because thestick circuits for the U relays include the windings of the SU relayswhich insures proper operation of the U chain.

The pick-up circuit for relay 3U when all of the M relays of themultiple chain are deenergized passes from battery B through a normalcontact 42 -'42a. of relay NX, front contact 54 of relay 2U,

the winding of relay 3U, wire 232, back contact (SS-63a of each of therelays 5M, 4M, 3M, 2M and EM, and winding 68 of relay MX to terminal Cof the source. When relay IM is picked up, the pick-up circuit for relay3U on the next round trip of operation of the unit chain will pass frombattery B through contact 4242a of relay NX, front contact 54 of relay2U, the'winding of relay 3U, wire 232, back contact 63-63a of relays 5M,4M, 3M and 2M, front contact 63-43311 of relay IM, and the winding ofrelay MX to terminal C. Each time a succeeding one of the M relays ofthe multiple chain picks up, its front contact will be included in thepick-up circuit which next becomes closed for relay 3U, as will beobvious.

It should be noted that with the pick-up circults for relay 3U arrangedin this manner, the windings 6.5 and'68 ofrelayMX will be alternatelyenergized in response tosuccessive energizations :of the relay 3U,whereby the relay 'MX is caused to alternately open and close its polarcontacts to effect the successive energization of the relays of themultiple chain in the same manner as in Fig.1.

The pick-up circuit for relay I'M in Fig. 2 is closed by the picking upof relay EU, and when this circuit becomes closed if an odd-numberedtrack relay is then picked up, this circuit passes from terminal Bthrough back contact 33'3 3b of each of the track relays in advance ofthe pickedup track relay, front contact '333'3a of the picked-up trackrelay, the winding of relay ISU,

.back contact IS-43a of relay ZSU, front contact 495.3b-of relay |SU,wire 50, back contact 60 of each of the relays -5-M, lM, 3M and 2M,normal contact 234 of relay MX, front contact 233 of relay EU and thewinding of relay IM to terminal-C.

The pick-up circuit for relay IM when any of the even-numbered trackrelays ZTR, 4TB. or STR .is then picked up passes from terminal Bthrough back contact -3333b of each track relay in advance of thepicked-up track relay, front contact 33-43:]. of thepi-cked-up trackrelay, the

winding of relay 2SU, back'contact 4949a of relay i'SU, front contact13-131) of relay ZSU, wire a back contact ED of each of the relays 5M,-M, 3M and 2M, normal contact 234 of relay MX, front contact 233 ofrelay -6U, and the winding of relay IM to -terminalC.

The stick circuits for relay 3U in Fig. 2 differ from the stick circuitsfor relay 3U in Fig. .l in the same manner that the pick-up circuits forrelay SU in Fig. 2 differ from the pick-up circuits for relay 3U inFig. 1. It is believed, therefore, that these stick circuits will beobvious from an inspection of the drawing without further detaileddescription.

The operation of the time measuring means as a whole with the apparatusconstructed as shown in Fig. 2a is essentially the same as the operationof the apparatus shown in Fig. la, it being noted that with theapparatus shown in Fig. 2a the NX and PX relays are set into operationby'the picking up of the ISU or .ZSU relay in response to the picking upof a track relay and are subsequently maintained in operation until suchtrack relay releases. With the relays NX and PX in operation, the relaysof the unit and multiple chains will function to register the time therelays NX and PX remain in operation to thereby measure the speed of acar traversing the track circuited stretch through the retarder. Sincethe operation of the time measuring apparatus shown in Fig. 2a isessentially the same as that shown in Fig. la, a detailed description ofthe operation of this portion of the apparatus is believed to beunnecessary.

The operation as a whole of the aparatus shown in Figs. 2 and 2a is asfollows: When the manually operable switch MS occupies the positionshown, the apparatus is conditioned for the control of the car -retarderby the lever L. Lever L is shown in its position and when the leveroccupies this position, all circuits for valve V2 are open and valve VIis energized over a circuit which passes from terminal B through contact20|-20l a of manually operable switch MS, contact 25 of lever L, linewire H5, wires H6 and 203, and the winding M of valve VI to terminal C.Since valve V2 is deenergized and valve Vi is energized, the brakingbars are held in their non-braking positions by the spring Ill.

I shall now assume that with the apparatus conditioned to be controlledby the lever L, the operator moves the lever from its 100 to its plposition to slow down a car which is approaching the retarder to themaximum control speed for which the apparatus is designed. The movementof lever L from its 120 to its pl position interrupts the circuit whichwas previously closed for valve VI and completes one or the other of twocircuits for valve V2 depending upon Whether relay LP is then energizedor deenergized. Assuming that relay LP is energized as shown in thedrawing, the circuit for valve V2 passes from terminal 38 throughcontact 29I-2illa of switch MS, contact 29 of lever L, wire 235, backcontact 236235a of relay lPil, back contact 231-231a of relay HP, frontcontact 238-238b of relay LP, wire 239, contact 2222a of pressureresponsive device P4555, wire 205, and the Winding H! of valve V2 toterminal C. Valve V2 will therefore become energized and will admitfluid pressure to cylinder 4 of motor M until the pressure in the cy1-inder increases to 45 pounds per square inch, whereupon the pressureresponsive device P4555 will function to maintain the pressure in themotor at a pressure of between 45 and 55 pounds per square inch.

If new with lever L in its pi position and with relay LP picked up,relay lP becomes picked up due to the speed of the car passing throughthe retarder decreasing to the value at which relay lP becomes pickedup, the circuit which was previously closed for valve V2 will becomeinterrupted at back contact 2237-4370; of relay IP, and a circuit willbecome closed for valve V I passing from terminal B through contact28l20la of manually operable switch MS, contact 29 of lever L, wire 235,back contact 236-43611 of relay lPil, front contact ESL-2375 of relaylP, front contact MEL-24Gb of relay LP, wire 241, contact El lo ofpressure responsive device P2El3G, asymmetric unit 265 in its lowresistance direction and the winding of valve VI to terminal 0. Valve Viwill therefore become energized and will vent fluid pressure fromcylinder 4 of motor M until the pressure decreases to 20 pounds persquare inch whereupon pressure responsive device P2ii--3il will thenfunction to maintain the pressure of the fluid in motor M at a pressureof between 2%) and 30 pounds per square inch.

If when lever L was moved to its pl position relay LP had then beendeenergized, valve V2 would then have become energized over a circuitwhich passes from battery B through contact 20 l-2illa of manuallyoperable switch MS, contact 29 of lever L, wire 235, back contact23-5236 a of relay IPG, back contact 25'!231a of relay IP, back contact238238c of relay LP, wire 242, and the winding 14 of valve V2 toterminal C. Under these conditions, none of the pressure responsivedevices is included in the control of the valve V2, and it will beapparent therefore that the resultant energizaticn of the valve V2 wouldcause fluid at full line pressure to be sup plied to motor M.

If, with lever L in its pl position and relay LP deenergized, relay IPbecomes energized due to the speed of the car decreasing to the properspeed, the circuit previously traced for valve V2 would then becomeinterrupted at back contact 231-23154 of relay IP and acircuit wouldbecome closed for valve VI at front contact 231-231b of relay IP whichlatter circuit may be traced from battery B through contact |2IJI a ofmanually operable switch MS, contact 29 of lever L, wire 235, backcontact 236-236a of relay IPO, front contact 23l231b of relay IP, backcontact 240-24011 of relay LP, wire 239, contact 22-22b of pressureresponsive device P45-55, asymmetric unit 235 in its low resistancedirection, and the winding 14 of valve VI to terminal 0. Valve VI willtherefore become energized and will vent fluid from cylinder 4 of motorM until the pressure decreases to 45 pounds per square inch at whichtime the pressure responsive device P45-55 will function to subsequentlymaintain the pressure of the fluid in cylinder 4 of motor M at thepressure of between 45 and 55 pounds per square inch.

If, when lever L occupies its 131 position, the speed of the cardecreases sufficiently to cause relay IPO to pick up, all circuitspreviously traced for valve V and VI will become interrupted and acircuit for valve VI will become closed passing from battery B throughcontact 20l-20 la of manually operable switch MS, contact 29 of lever L,wire 235, front contact 236236b of pressure responsive device [P0, wireH6, and the winding of valve VI to terminal C. Valve V! will thereforebecome energized and will vent the fluid which was previously suppliedto the motor M to atmosphere to thereby permit the spring 16 to move thebraking bars to their non-braking or released positions.

It will be seen, therefore, that when lever L is moved to its plposition, cylinder 4 of motor M will be supplied with fluid at full linepressure or at approximately half full line pressure according, as relayLP is then released or is picked up. It will also be apparent that ifrelay LP is picked up when relay IP becomes deenergized, the pressurewill be decreased from a pressure of between 45 and 55 pounds to apressure of between 20 and 30 pounds, whereas if relay IP becomes pickedup when relay LP is released, the pressure of the fluid in motor M willbe decreased from full line pressure to a pressure of between andpounds.

It should be noted that relay LP can be picked up or released at thewill of the operator by merely operating the switch MSI, and it follows,therefore, that when the lever occupies its pl position, the operatorcan change the base pressure at which the retarder operates from thefull line pressure to half line pressure or vice versa at will. Thisfeature is particularly desirable in yards where some of the cars areheavy cars and other cars are light weight cars, and permits theoperator to make the desired selection between the braking force whichwill be applied to the heavy cars and the braking force which will beapplied to the light cars to thereby prevent derailment of the lightcars.

The operation of the apparatus when lever L is moved to its 102 or 103position is similar in all respects to that just described for theoperation of the apparatus when lever L is moved to its pi position withthe exception that under these latter conditions the speed at which the1P relay picks up will be different from the speeds which this relaypicked up when the lever occupied its pl position. It is believed,therefore, that this operation will be understood from

